Modular support assemblies, such as shelving, are generally well known in the art. These devices typically separate, individual vertical support members, such as posts or panels, and horizontal shelf panels. Various mechanisms are then employed to connect the horizontal panels to the vertical support members, some examples of which are disclosed in U.S. Pat. No. 6,634,511 to Manghera, in U.S. Pat. No. D479,925 to Hsieh at al., in U.S. Pat. No. 6,260,488 to Yang et al., and in U.S. Pat. No. 6,722,292 to Salmanson.
One method that has been employed to create such support assemblies is the use of blow molding. Typically, this process involves the use of a mold consisting of two separate halves or portions having cavities of particularly desired shapes and sizes. Usually, one extrudes a large-diameter, sealed tube of molten material (commonly referred to as a “parison”), places the tube between the mold halves, and closes the mold around the tube. Fluid pressure is then introduced into the tube, forcing the molten tube against the walls of the cavities, conforming the tube to the shape thereof. The pressure is maintained until the molten material cools and solidifies. The pressure is then released, the mold halves are pulled apart, and the hardened article is ejected therefrom. An example of this process is disclosed in U.S. patent application Ser. No. 10/958,824 in the names of Bahnsen et al., the specification of which is incorporated herein by reference.
Because this is a relatively simple way of producing a double wall article, which is both inexpensive and lightweight, yet durable, it is not uncommon to use this method for manufacturing support structures, such as shelving. By producing the panels in this manner, one is able to produce shelving that is relatively strong despite its lighweight character, such as is disclosed in U.S. Pat. No. 4,998,023 to Kitts.
However, one disadvantage that remains with many of these systems is that assembling and disassembling the support structures can still be time consuming and often requires special tools. Another significant disadvantage of the aforementioned blow-molded structures and other plastic assemblies is that the rigidity of the horizontal panels, though good, is still limited. Therefore, depending in part on both the length and the specific thickness of the walls of the panel, the shelf will only be able to bear a certain amount of weight before beginning to bow under the stress.
Accordingly, it has been suggested to strengthen these support assemblies by altering the structure of the shelf panel. An example of such a system is disclosed in U.S. Pat. No. 6,826,887 to Skov. By blow molding a panel such with a multitude of transverse or lateral beams and ribs disposed within the beam that project from a first panel to a second panel thereby providing additional support to weight bearing surface.
However, assemblies such as these not only require detailed mold designs to create the various beams and ribs, but still result in structures that, due to their extended, horizontal nature, have a limited strength to weight ratio.
What is desired, therefore, is modular support assembly that easy to assemble and disassemble. What is further desired is modular support assembly that is both lightweight and also able to bear a lot of weight. What is also desired is modular support assembly that can be manufactured easily and inexpensively.